The present invention relates to an agricultural working machine with intake conveyor mechanisms which are hydraulically driven via a hydraulic circuit.
A system of this type was made known in DE 100 36 612 A1, for example. According to that publication, the hydraulically-driven intake conveyor mechanisms—which are designed as intake rollers provided in pairs—convey a flow of crop material between them, the crop-material flow being transferred in the rear region to a crop-material chopping device, such as a chopper drum. Since the crop-material flow often contains foreign objects, such as metallic pieces or stones, which can cause serious damage to the chopper drum as it rotates at a high rate of speed, a “quick stop” function is assigned to the intake conveyor mechanisms. With the “quick stop” function, the foreign objects located in the crop-material flow are detected using a detection device, and, as a function of their detection, a shut-off signal for the intake conveyor mechanisms is generated in a control unit. To reliably prevent the detected foreign objects from reaching the chopper drum anyway after the intake conveyor mechanisms are shut off but continue to move, it is provided according to DE 100 36 612 A1 that a valve combination be assigned to the hydraulic drive of the intake conveyor mechanisms, the valve combination being composed of a main control valve and a pilot directional control valve, the foreign object detection device immediately triggering—when foreign objects are detected—a switching procedure at the pilot directional control valve that induces the quick stop. In addition to the large number of components required to realize the quick-stop function, a design of this type has the disadvantage that the various switching procedures and the distances that must be covered by the switching medium can delay the quick stop procedure such that the detected foreign object reaches the rotating chopper drum anyway, where it causes considerable damage.
The problem of inadequate reaction time is alleviated in the related art as disclosed, e.g., in DE 100 21 663 A1, by increasing the number of pairs of intake conveyor mechanisms, so that the length of the path traveled by the crop material through the intake conveyor mechanisms increases, thereby increasing the amount of time the crop material spends in the intake conveyor mechanisms. The interval of time that passes before the intake conveyor mechanisms come to a stop is therefore increased, thereby ensuring, with a greater level of reliability, that the foreign objects will be prevented from reaching the effective region of the rotating chopper drum. A design of this type has the disadvantage, however, that it would require a further, high-cost stage of intake rollers, which would also increase the amount of installation space required.